Cascade insert with JPA/Hibernate (EclipseLink)

I have two tables like this

|      PERSON       |     |    EMPLOYEE     |
|  id  |  fullName  |     | personId | code |

EMPLOYEE.personId is a primary key as well as foreign key pointing to PERSON.id

I have these two classes:

@Entity
@Table(name="PERSON")
@Inheritance(strategy=InheritanceType.JOINED)
public abstract class Person 
                  implements Serializable {
    protected int id;
    protected String fullName;

    @Id
    @Column("id")
    public int getId() {
         return this.id
    }

    public void setId(int id) {
        this.id = id;
    }

    @Column("fullName")
    public int getFullName() {
         return this.fullName
    }

    public void setId(int fullName) {
        this.fullName = fullName;
    }

}

@Entity
@Table(name="EMPLOYEE")
@PrimaryKeyJoinColumn(name="personId")
public class Employee extends Person
        implements Serializable {

    pr开发者_如何学编程ivate String code;

    public Employee(String code) {
        setCode(code);
    }

    @Column("code")
    public String getCode() {
         return this.code
    }

    public void setCode(String code) {
        this.code = code;
    }

}

And when I wanna insert a new record into EMPLOYEE table:

entityTransaction.begin();
Employee emp = new Employee("EMP001");
emp.setFullName("hiri");
this.entityManager.persist(emp);
entityTransaction.commit();

It throws an exception says:

Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (...)
Error Code: 1452
Call: INSERT INTO EMPLOYEE (code, personId) VALUES (?, ?)
    bind => [EMP001, 0]

As you can see, it is supposed to insert a new Person record first an Employee after that, but in fact it doesn't, the foreign key personId=0 causes the problem. Can you help me? Thanks!

You do not need @PrimaryKeyJoinColumn when using Inheritance. It will be managed for you automatically. You do need to have a unique ID value though. If you intend to use sequence generation you need to add @GeneratedValue to the id.

    @Id
    @GeneratedValue
    @Column("id")
    public int getId() {
        return this.id
    }